Aluminum-Silicon alloys are being used with increasing frequency in the automotive industry due to their low density relative to traditional materials. When production problems occur during the machining of these alloys, the issues are often attributed to microstructure/casting difficulties. However, the influence of microstructure on the machinability of Al-Si alloys is not clearly understood. This lack of understanding limits the commercial application of these alloys. This research is directed at the development of a machining force model that addresses key microstructural features of 319 Aluminum. A machining force model was developed based on an enhanced version of Zheng's Continuum Mechanics model that incorporates microstructural effects. Machining experiments identified Secondary Dendrite Arm Spacing (SDAS) as a significant microstructure feature of 319 aluminum in terms of machinability. A new material constitutive relationship that incorporates SDAS microstructure effects on the flow stress was proposed.; Disk turning tests are performed to simulate the orthogonal cutting process. The cutting forces obtained from some of these tests are used in concert with an inverse form of the enhanced continuum mechanics machining model to estimate the parameters in the material constitutive equation. The enhanced continuum mechanics orthogonal cutting model is then applied to predict cutting forces when machining A1319. Comparison of the model predicted and experimentally acquired cutting forces is demonstrated to show good agreement.
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